This invention belongs to the field of material haulage vehicles and more particularly to improvements in the type commonly known as "shuttle cars" for hauling loose mined material in underground mines.
Shuttle cars must operate in mine rooms and entries where the bottom and the top undulate, where height and space restrictions are severe, and where turning radiuses are tight. Yet they must provide large capacity along with rapid loading, carrying, and unloading of mined material in great tonnages. As shown for example in Russell U.S. Pat. No. 2,962,176, vertically articulated shuttle cars have been developed for low height, undulating passages. As the contour of the floor changes, fore and aft body sections pivot about a horizontal axis to prevent the underside or topside of the car from hanging up on the floor or roof.
However, in many mines it would be physically impossible for shuttle cars of adequate capacity to make the tight turns encountered without "brushing" the corners, i.e. blasting them off to eliminate the sharp turns. This, of course, is wasteful of labor and energy and could be avoided if shuttle cars could articulate horizontally to avoid the sharp corners, as shown in FIG. 16.
Attempts have been made to provide horizontal articulation in a mine haulage vehicle by using ejector scoops and shovel loaders. Examples are shown in U.S. Pat. No. 3,937,345 and the following equipment advertisements in the April 1976 Coal Age: pages 58 and 59, showing ejector buckets manufactured by Wagner Mining Equipment Co.; page 166, an ejector bucket manufactured by Fairchild Inc.; page 173, a scoop manufactured by Owens Mfg. Inc.; page 196, ram cars manufactured by Dresser Industries; page 205, a scoop/tractor manufactured by Pyott-Boone, Inc.; page 268, an ejector scoop manufactured by S & S Corporation; and pages 374, 375, an ejector scoop manufactured by Eimco Mining Machinery.
Although these units have a tractor section and a cargo section pivotally interconnected for horizontal swinging movement, they have a very serious drawback in that loading and unloading must both be done from the scoop or shovel end, requiring the machine to make two full 180.degree. turns on each trip between the loading and unloading sites. This takes time and often requires brushing out a turn-around area which otherwise would be unnecessary.
There is a need for a horizontally articulated mine haulage vehicle which can receive a load at one end, convey it in one direction through the vehicle, and discharge it from the other end without turning the vehicle around.